The invention relates to a thermoelectric level detector and more particularly to a tank level indicator, for use in vehicles, for example. The level indicator has a current carrying impedance path, the impedance of which depends on temperature and is a measure of the liquid level which is to be ascertained. The impedance value which depends on the liquid level is generally measured in such a device and is converted preferably electronically into an indication of the level.
More particularly, an important feature of such a thermoelectric level detector is that there is a resistance path through which current flows, a predetermined voltage dropping across said resistance path as the current flows therethrough. This voltage depends on cooling by the liquid. The higher the level of liquid to be detected, the more liquid there is and the greater is the cooling of the resistance path. The resistance of the path depends on temperature so that the path voltage depends on the cooling and therefore on the level of the liquid surrounding it, so that the detected voltage can be used to give an indication of the liquid level. This use of a resistance path in a thermoelectric level detector is known in the art and is described, for example, in U.S. Pat. No. 1,942,281, issued on Jan. 2nd, 1934 to Emil Duhme, which is incorporated herein by reference.